Joint arthroplasty is a well-known surgical procedure by which a diseased and/or damaged natural joint is replaced by a prosthetic joint. A typical knee prosthesis includes a tibial tray, a femoral component, and a polymer insert or bearing positioned between the tibial tray and the femoral component. The femoral component generally includes a pair of spaced apart condylar portions, the surfaces of which articulate with corresponding surfaces of the polymer bearing. The femoral component may include a stem or post that is implanted into the intramedullary canal of the distal end of the femur to provide stability. In some applications, a stem extension may be coupled to the femoral component to increase the overall length of the stem of the femoral component.